xiaoxiang781216 commented on a change in pull request #5782:
URL: https://github.com/apache/incubator-nuttx/pull/5782#discussion_r834451712
##########
File path: arch/risc-v/src/common/riscv_assert.c
##########
@@ -338,6 +338,10 @@ static void riscv_dumpstate(void)
else
{
riscv_saveusercontext(rtcb->xcp.regs);
+
+ /* riscv_saveusercontext modifies the local context (a0), restore it */
+
+ rtcb = running_task();
Review comment:
toolchain will save rtcb before inovke riscv_saveusercontext if it is
still used later?
##########
File path: arch/risc-v/src/common/riscv_swint.c
##########
@@ -196,12 +229,14 @@ int riscv_swint(int irq, void *context, void *arg)
* save register space references in the saved A1 and return.
*/
+#ifndef CONFIG_ARCH_USE_S_MODE
Review comment:
let's use one pair of #ifndef/#endif to guard all special syscall?
##########
File path: arch/risc-v/include/syscall.h
##########
@@ -391,6 +396,64 @@ static inline uintptr_t sys_call6(unsigned int nbr,
uintptr_t parm1,
return r0;
}
+#ifdef CONFIG_ARCH_USE_S_MODE
+
+/* In S-mode the kernel cannot ecall to itself, because ecall will raise
+ * privileges to M-mode, which is not what we want. Instead, use the syscall
+ * trampoline to do the same.
+ */
+
+static inline uintptr_t ksys_call3(unsigned int nbr, uintptr_t parm1,
+ uintptr_t parm2, uintptr_t parm3)
+{
+ register long r0 asm("a0") = (long)(nbr);
+ register long r1 asm("a1") = (long)(parm1);
+ register long r2 asm("a2") = (long)(parm2);
+ register long r3 asm("a3") = (long)(parm3);
+
+ asm volatile
+ (
+ " addi sp, sp, -16\n" /* Make room */
+ " sd ra, 0(sp)\n" /* Save ra */
+ " jal ra, riscv_syscall_dispatch\n" /* Dispatch (modifies ra) */
+ " ld ra, 0(sp)\n" /* Restore ra */
+ " addi sp, sp, 16\n" /* Restore sp */
+ :: "r"(r0), "r"(r1), "r"(r2), "r"(r3)
+ : "memory"
+ );
+
+ asm volatile("nop" : "=r"(r0));
+
+ return r0;
+}
+
+static inline uintptr_t ksys_call4(unsigned int nbr, uintptr_t parm1,
Review comment:
remove too
##########
File path: arch/risc-v/include/mode.h
##########
@@ -0,0 +1,91 @@
+/****************************************************************************
+ * arch/risc-v/include/mode.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_RISC_V_INCLUDE_MODE_H
+#define __ARCH_RISC_V_INCLUDE_MODE_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <arch/csr.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#ifdef CONFIG_ARCH_USE_S_MODE
+
+/* CSR definitions */
+
+# define CSR_STATUS sstatus /* Global status register */
+# define CSR_EPC sepc /* Exception program counter */
+# define CSR_IE sie /* Interrupt enable register */
+
+/* In status register */
+
+# define STATUS_IE SSTATUS_SIE /* Global interrupt enable */
+# define STATUS_PIE SSTATUS_SPIE /* Previous interrupt enable */
+# define STATUS_PPP SSTATUS_SPPS /* Previous privilege */
+# define STATUS_SUM SSTATUS_SUM /* Access to user memory */
+
+/* Interrupt bits */
+
+# define IE_EIE SIE_SEIE /* External interrupt enable */
+# define IE_SIE SIE_SSIE /* Software interrupt enable */
+# define IE_TIE SIE_STIE /* Timer interrupt enable */
+
+/* External, timer and software interrupt */
+
+# define RISCV_IRQ_EXT RISCV_IRQ_SEXT /* PLIC IRQ */
Review comment:
and irq to irq.h too, so we don't need special mode.h header file
##########
File path: arch/risc-v/src/mpfs/Make.defs
##########
@@ -34,6 +34,14 @@ CMN_CSRCS += riscv_mdelay.c riscv_udelay.c
riscv_copyfullstate.c
CMN_CSRCS += riscv_idle.c riscv_tcbinfo.c riscv_getnewintctx.c
CMN_CSRCS += riscv_cpuindex.c
+# If the NuttX kernel runs in S-mode
+
+ifeq ($(CONFIG_ARCH_USE_S_MODE),y)
+CMN_ASRCS += riscv_exception_macros.S riscv_machine_trap.S riscv_context.S
Review comment:
don't need add riscv_exception_macros.S and riscv_machine_trap.S doesn't
exist? it's better to add a defconfig which eanble S mode, so we can catch the
compiler issue.
##########
File path: arch/risc-v/include/mode.h
##########
@@ -0,0 +1,91 @@
+/****************************************************************************
+ * arch/risc-v/include/mode.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_RISC_V_INCLUDE_MODE_H
+#define __ARCH_RISC_V_INCLUDE_MODE_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <arch/csr.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#ifdef CONFIG_ARCH_USE_S_MODE
+
+/* CSR definitions */
+
+# define CSR_STATUS sstatus /* Global status register */
Review comment:
should we move the general CSR definition to csr.h
##########
File path: arch/risc-v/include/syscall.h
##########
@@ -128,6 +130,8 @@
/* Context switching system calls *******************************************/
+#ifndef CONFIG_ARCH_USE_S_MODE
Review comment:
let's move all context switch macro to riscv_internal.h
##########
File path: arch/risc-v/include/syscall.h
##########
@@ -391,6 +396,64 @@ static inline uintptr_t sys_call6(unsigned int nbr,
uintptr_t parm1,
return r0;
}
+#ifdef CONFIG_ARCH_USE_S_MODE
+
+/* In S-mode the kernel cannot ecall to itself, because ecall will raise
+ * privileges to M-mode, which is not what we want. Instead, use the syscall
+ * trampoline to do the same.
+ */
+
+static inline uintptr_t ksys_call3(unsigned int nbr, uintptr_t parm1,
Review comment:
remove nobody call ksys_call3/ksys_call4 now?
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